Many people working with nanomaterials such as carbon nanotubes, buckminster fullerenes, and graphene nanoplatelets have relied on dispersants, surfactants or stabilizing molecules, such as polyvinyl pyrrolidone, sodium dodecyl benzene sulfonate, octyl phenol ethoxylate, or other surfactants to achieve a stable and effective dispersion of the nano particles in the media of choice. This is frequently required for further utilization and incorporation into other products.
Many of these materials do not disperse well in liquid or solid phase dispersion processes, are hydrophobic, and are highly prone to intermolecular Van der Waals forces which make them start to reagglomerate soon after the dispersion process has finished. Working with solid phase processes poses an additional health and safety concern. The nanomaterials can become airborne and thus present an inhalation hazard or provide for other routes of entry into the human body. Dispersion issues have hampered the wide spread acceptance of these nanoparticles by industry. Achieving a stable dispersion that can be further processed by industry remains challenging. Typically, surfactants such as Polyvinyl Pyrrolidone (PVP), Sodium Dodecyl Sulfonate (SDS) Sodium Dodecyl Benzene Sulfonate (SDBS), octyl phenol ethoxylate, or other dispersants, surfactants or stabilizing molecules are used to keep the nanotubes, fullerenes, graphene, or graphene nano platelets well separated and dispersed in the solvent of choice. However, these surfactants interfere with the nanomaterials mechanical, kinetic, optical, electrical or thermal conductivity properties which many people working with these materials desire to exploit and the surfactant often must be removed by repeated washing and rinsing or heating. Some surfactants like PVP can't be successfully removed.
The alternative method of dispersing nanoparticles in the liquid phase involves adding functional groups to the nanoparticles being utilized which also introduces defects to their physical structure and negatively effects some of their inherent properties such as mechanical strength and conductivity. The intermolecular Van der Waals forces present in the nanotubes, buckminster fullerenes, graphene, or graphene nanoplatelets make these nanoparticles especially prone to reagglomeration which is detrimental to their use by research and industry.